As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT RETURNED TO PHX ON ACCOUNT OF RIGHT ENGINE OIL QUANTITY DROPPING. EMERGENCY WAS DECLARED BY ATC. PILOT REPORTS RT ENGINE SUDDENLY LOST OIL QUANTITY FROM 19 TO 5, GRADUAL LOSS FROM 5 TO 2.5 THEN BACK TO 9.0, OIL PRESSURE THROUGHOUT WAS NORMAL. MAINTENANCE TROUBLESHOT AND AN ENGINE CHANGE WAS DECLARED. MAINTENANCE REMOVED AND REPLACED RIGHT ENGINE IAW JOB CARDS 26L40071004 AND 26L0007101.